Our copending application 09/788,418, also entitled xe2x80x9cCONTROLLER FOR AUTOMATIC TRANSMISSIONxe2x80x9d and filed on even date herewith, describes and claims related subject matter.
1. Field of the Invention
The present invention relates to an automatic transmission controller which is capable of changing shift timing in accordance with type of driver.
2. Related Art
One type of known controller changes shift timing from that for a normal flat road hereinafter simply referred to as xe2x80x9cstandard shift timingxe2x80x9d) in accordance with actual running road conditions such as a hilly road or curvy road.
However, the shift timing has been changed corresponding only to the road condition or the driving style with respect to the standard shift timing in either case and no technology has yet been developed to reflect driving style where the shift timing has been changed from the standard shift timing in accordance with road conditions. Further, there is the problem of applying judgment regarding driving style on a flat road to a non-flat road, such as an uphill slope.
More specifically, because the extent of accelerator pedal depression increases in uphill running as compared to the case of running on a flat road, there is the possibility that an economy type driver, whose accelerator pedal depression is small on a flat road, will be judged to be a sport type driver on the basis of measurement of accelerator pedal depression in uphill running, and the control thereafter will not fit the driving style of the driver if the driving style is determined based solely on measurement of accelerator pedal depression.
Further, although the shift timing is normally switched to uphill shift timing upon start of uphill running, after running a flat road in a mid gear range with the sport type shift timing, a problem arises when an upshift is made even though the driver wants to continue to drive the current gear stage when the downshift timing for the current gear stage has been set more to the high-speed side than that for the sport type shift timing.
Moreover, when the shift timing is changed from the standard shift timing for an economy type driver in running around a corner or curve, an upshift is carried out quickly, which is unsatisfactory for a sport type driver. Conversely, when the shift timing is changed from the standard shift timing for a sport type driver in going around a curve or corner, the upshift is not carried out sufficiently soon to satisfy the economy type driver. Accordingly, the problem of how to reflect the driving style of a driver in cornering remains unsolved.
Accordingly, it is an object of the invention to provide an automatic transmission controller which is capable of changing shift timing in accordance with both the road running conditions, such as an uphill running and cornering, and the driving style of the driver.
According to a first aspect of the invention, an automatic transmission controller capable of detecting running road conditions, such as uphill running and going around a curve or corner, and of changing shift timing of a transmission in accordance with the detected road running conditions includes driver type judging means for generating a judgment output related to the driver type based on the driving conditions of the vehicle and for judging the driver type based on the judgment output. The controller further includes shift timing determination means for determining a shift timing corresponding to the road conditions and corresponding to the driver type, e.g., one of sport type, medium type and economy type, as judged by the driver type judging means, and shift control means for controlling the transmission based on the shift timing determined by the shift timing determining means.
For example, according to the first aspect of the invention, uphill running could dictate selection of an uphill road mode shift map and the determined driver type could dictate selection of one of a plurality of such shift maps, e.g. an uphill road mode 1 shift map UP-SLOPE1 wherein an upshift is inhibited in a predetermined corner section and an uphill road mode 2 shift map UP-SLOPE2. Alternatively, rather than selection between plural shift maps, the judgement of driver type could be applied to dictate an increase in the area of the upshift inhibiting section of a single shift map selected in accordance with road conditions. Thus, the shift timing may be changed not only by the road condition but also in a manner reflecting the driving style of the driver, allowing for finer shift control.
According to a second aspect of the invention, the driver type judging means generates a judgment output related to the driver type, the driving conditions of the vehicle and judges the driver type separately for different road conditions, e.g. separately for an uphill grade and for a flat road, based on the judgment output; and the shift timing changing means changes the shift timing according to the judged driver type. By judging the driving style separately for running on a flat road and for running on an uphill grade, the control may better account for the driving style of each individual driver, including a driver who has various driving styles for different road conditions.
The judgment output may be a value on a scale having lower and upper limits defined by a first value, e.g., 0, and a second value e.g., 100, which is greater than the first value, i.e., a scale of 0 to 100. Further, the judgment output may be based on average vehicle speed, duration (time) of accelerator high opening and average speed of accelerator pedal depression or average speed of throttle opening (as shown in FIG. 5 for example).
The driver type judging means may judge the driver type as belonging to one of a plurality of categories, e.g., a sport type, an economy type and a medium type, intermediate the sport and economy.
In a preferred embodiment, the driver type judging means judges the driver type separately for a flat road and for a non-flat road to generate judgment outputs as values on a scale of, e.g. 0 to 100, and judges the driver type as one of a sport type, an economy type and one or more types positioned between them based on the judgment output. For a given driver, a reference value on the sport type side (A greater than Axe2x80x2, Bxe2x80x2 greater than B, Cxe2x80x2 greater than C, Dxe2x80x2 greater than D) is used in the judgment for a non-flat road, wherein the fuzzy outputs Axe2x80x2, Bxe2x80x2, Cxe2x80x2, Dxe2x80x2 are for an uphill grade whereas the fuzzy outputs are A, B, C and D are for running on a flat road. In this manner it becomes possible to prevent an economy type driver, for example, from being erroneously judged to be a sport type driver when the economy type driver steps on the accelerator on an uphill grade.
In another preferred embodiment, the shift timing changing means changes the shift timing for the non-flat road so that a low-speed side gear stage is readily selected when the driver type judged by the driver type judging means is the sport type. This prevents an upshift when a sport type driver wants to continue running in the current gear stage when the vehicle makes the transition from a flat road to a non-flat road while running in an intermediate gear stage.
The shift timing changing means may include a memory containing stored therein a plurality of shift maps for running an uphill grade, e.g., an uphill road mode 1 shift map limit UP-SLOPE1 and an uphill road mode 2 shift map UP-SLOPE2, and selects a specific shift timing map from among the plurality of shift timing maps based on the driver type judged by the driver type judging means to determine shift timing in running the uphill slope. For example, where the first uphill shift map of the shift timing judgment changing means is a steep uphill road shift map and the second uphill road shift map is a moderate uphill road shift map, the shift timing changing means may be set to always select the steep uphill road shift map when the driver type judged by the driver type judging means is the sport type, so as to prevent an upshift from being made even though the sport type driver wants to continue to run with the current gear stage when the vehicle goes from a flat road onto a non-flat road while running with an intermediate gear stage.
Alternatively, the shift timing changing means may be set so that the low-speed side gear stage is selected rather than the shift timing (sport mode map SPORT) for running a flat road when the driver type is the sport type, so that it is possible to prevent an upshift from being made even though the driver wants to continue to run in the current gear stage.
In yet another embodiment, the shift timing changing means (SUB4) changes an upshift inhibiting section, e.g., corner section, of a shift map. This embodiment offers the advantage of simplicity.
In yet another embodiment, the shift timing changing means changes the upshift inhibiting section of a shift map in accordance with the degree of inclination of the uphill grade and with the driver type judged by the driver type judging means.
The above and other advantages of the invention will become more apparent in the following description and the accompanying drawings.
The entire teachings of Japanese Application No. 2000-45732, filed Feb. 23, 2000 are incorporated herein in their entirety, inclusive of the specification, claims and drawings. Likewise, the entire teachings of our copending application of the same title, filed on even date herewith, are incorporated herein by reference.